Caves are dark, wet habitats that support unique plant and animal life adapted to live without light. Common cave animals include blind salamanders, fish, crayfish and bats, while bacteria and fungi serve as cave plants. Caves have three zones - the entrance, twilight and dark zones - and come in different types like ice caves, sea caves and lava tubes. Cave life exhibits adaptations like lack of vision, use of guano for energy, and echolocation in bats.